1/2 a fluid ounce or 1.5 centilitres of Ouzo
1/2 a fluid ounce or 1.5 centilitres of Kahlua
1/2 a fluid ounce or 1.5 centilitres of Tequila

Layer in a shot glass in the given order. If it's available in your area I suggest purchasing a home bar companion called Shooters made Easy. A small tray with 4 shooter glasses, another tray fits on top of glasses. Small holes in the top tray allow layering perfect every time. Regardless of order.